html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/5224#issuecomment-828294723,https://api.github.com/repos/pydata/xarray/issues/5224,828294723,MDEyOklzc3VlQ29tbWVudDgyODI5NDcyMw==,9010180,2021-04-28T09:14:34Z,2021-04-28T09:14:34Z,NONE,"> Could you kindly share the Python traceback from the error message?

Sorry, that was remiss of me. Here's the output from the test script above, including the traceback.

```
$ python test_append_bytes.py 
Creating |U1 Zarr...
Appending to |U1 Zarr with Zarr library...
Appending to |U1 Zarr with xarray...
Creating |S1 Zarr...
Appending to |S1 Zarr with Zarr library...
Appending to |S1 Zarr with xarray...
Traceback (most recent call last):
  File ""/home/pont/test_append_bytes.py"", line 21, in <module>
    test_append(""|S1"", ""test-s.zarr"")
  File ""/home/pont/test_append_bytes.py"", line 18, in test_append
    ds_to_append.to_zarr(zarr_path, mode=""a"")
  File ""/home/pont/loc/repos/xarray/xarray/core/dataset.py"", line 1877, in to_zarr
    return to_zarr(
  File ""/home/pont/loc/repos/xarray/xarray/backends/api.py"", line 1414, in to_zarr
    _validate_datatypes_for_zarr_append(dataset)
  File ""/home/pont/loc/repos/xarray/xarray/backends/api.py"", line 1261, in _validate_datatypes_for_zarr_append
    check_dtype(k)
  File ""/home/pont/loc/repos/xarray/xarray/backends/api.py"", line 1252, in check_dtype
    raise ValueError(
ValueError: Invalid dtype for data variable: <xarray.DataArray 'x' ()>
array(b'', dtype='|S1') dtype must be a subtype of number, datetime, bool, a fixed sized string, a fixed size unicode string or an object
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,868976909